Sabbath Clock

How this gets the time right

Sunset is computed from your own coordinates — the sun’s position worked out for your latitude and longitude, not looked up in a table for the nearest big city. It is the standard civil definition: the moment the sun’s upper edge meets the horizon, allowing for how the atmosphere bends the light.

It is checked against the US Naval Observatory — for Southfield, Sydney, London, Nairobi and Apia, which between them span both hemispheres, the solstice, the equator and the far side of the date line. All five match to the minute.